Re: [PATCH v3] LSM: use 32 bit compatible data types in LSM syscalls.

["Dmitry V. Levin" <ldv@strace.io>]

On Thu, Mar 14, 2024 at 11:30:53AM -0400, Paul Moore wrote:
> On Wed, Mar 13, 2024 at 4:07 PM Paul Moore <paul@paul-moore.com> wrote:
> > On Mar 13, 2024 Casey Schaufler <casey@schaufler-ca.com> wrote:
> > >
> > > LSM: use 32 bit compatible data types in LSM syscalls.
> > >
> > > Change the size parameters in lsm_list_modules(), lsm_set_self_attr()
> > > and lsm_get_self_attr() from size_t to u32. This avoids the need to
> > > have different interfaces for 32 and 64 bit systems.
> > >
> > > Cc: stable@vger.kernel.org
> > > Fixes: a04a1198088a: ("LSM: syscalls for current process attributes")
> > > Fixes: ad4aff9ec25f: ("LSM: Create lsm_list_modules system call")
> > > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> > > Reported-and-reviewed-by: Dmitry V. Levin <ldv@strace.io>
> > > ---
> > >  include/linux/lsm_hook_defs.h                        |  4 ++--
> > >  include/linux/security.h                             |  8 ++++----
> > >  security/apparmor/lsm.c                              |  4 ++--
> > >  security/lsm_syscalls.c                              | 10 +++++-----
> > >  security/security.c                                  | 12 ++++++------
> > >  security/selinux/hooks.c                             |  4 ++--
> > >  security/smack/smack_lsm.c                           |  4 ++--
> > >  tools/testing/selftests/lsm/common.h                 |  6 +++---
> > >  tools/testing/selftests/lsm/lsm_get_self_attr_test.c | 10 +++++-----
> > >  tools/testing/selftests/lsm/lsm_list_modules_test.c  |  8 ++++----
> > >  tools/testing/selftests/lsm/lsm_set_self_attr_test.c |  6 +++---
> > >  11 files changed, 38 insertions(+), 38 deletions(-)
> >
> > Okay, this looks better, I'm going to merge this into lsm/stable-6.9
> > and put it through the usual automated testing as well as a kselftest
> > run to make sure everything there is still okay.  Assuming all goes
> > well and no one raises any objections, I'll likely send this up to
> > Linus tomorrow.
> 
> I had to squash the code snippet below into the patch to address a
> build problem identified by the kernel build robot.  I'm going to keep
> Casey's sign-off and Dmitry's reported-reviewed tag as I feel this
> change is minor, but if anyone has any objections please let me know
> soon.
> 
> [NOTE: cut-n-paste'd into email, likely whitespace damage, but you get the idea]
> 
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 77eb9b0e7685..e619ac10cd23 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -960,10 +960,10 @@ asmlinkage long sys_cachestat(unsigned int fd,
>                struct cachestat __user *cstat, unsigned int flags);
> asmlinkage long sys_map_shadow_stack(unsigned long addr, unsigned long size, un
> signed int flags);
> asmlinkage long sys_lsm_get_self_attr(unsigned int attr, struct lsm_ctx *ctx,
> -                                     size_t *size, __u32 flags);
> +                                     u32 *size, u32 flags);
> asmlinkage long sys_lsm_set_self_attr(unsigned int attr, struct lsm_ctx *ctx,
> -                                     size_t size, __u32 flags);
> -asmlinkage long sys_lsm_list_modules(u64 *ids, size_t *size, u32 flags);
> +                                     u32 size, u32 flags);
> +asmlinkage long sys_lsm_list_modules(u64 *ids, u32 *size, u32 flags);

Fine with me, thanks.

btw, with the change above, u32 will become about twice more popular
in include/linux/syscalls.h than __u32.


-- 
ldv